Recently, 33 pier columns made of coal-bone environmentally friendly binder, measuring 1 meter in diameter and 2.8 meters in height, have been presented at the 12407 comprehensive working face of Shendong Ulanmulun Coal Mine, providing a strengthened support for the working face moving through the empty roadway as a substitute for the previous pumped concrete pillars and high polymer grouting materials. This is also the first domestic application of the pier column support technique made of coal-bone environmentally friendly binders.
Developed jointly by Shendong Company and Hebei University of Engineering, this support technique is a new type of coal-based concrete for mining that adopts the harmless binder to mix coal blocks with other solid waste materials. It boasts better pore permeability, damping effect and compressive strength than conventional cement, while allowing flexible adjustment of initial and final binding time and perfect adaptation to different support heights according to mold size.
"The pier column can be directly cut by coal machine for recycling because it is made of coal block as skeleton material (main raw material). While meeting the support safety and fast movement, it also eliminates the waste of resources. Moreover, the pier column support will hardly pollute the underground environment as compared with pumped concrete pillars and high polymer grouting materials, let alone the coal quality", said the leader of the comprehensive mining team I, who is responsible for mining the 12407 working face.
Reportedly, the 12407 working face has a length of 104 meters passing the empty roadway, where a total of 39 supporting pier columns to be arranged for recovering the coal resources of 110 tons more. The successful application of this technique in Ulan Mulun Coal Mine contributed to a new idea of coal mine support technique, also offered valuable experience and good demonstration for the application and promotion of coal-based binder.
